* support OD level and skip dynamic loss scaling for bf16

[AMP] Allow to enable multi_precision through paddle.static.amp.decorate and add documents for some apis. (#53012)

* Add document for some apis. test=docs_preview

* Allow to set master_weight in paddle.static.amp.decorate.

* Polish codes and add unittest.

* Refine docs.

* Remove the repetitive function.

* support promote dtype for static amp training

* unify o1 and o2

* update for unittest

* fix op_role

* add use_promote arg

* fix doc

* add promote unittest

* polish unittests

* fix controflow and test

* Implement a common AmpTestBase.

* Support overload of decorate.

* Change the ignore list of flake and fix an error.

* Unify the static amp codes of fp16 and bf16.

* Polish apis and add unittest.

* Add operator stats collecting tools for program.

* Add the check of number of bloat16 operators in unittest.

* Add warning for operator not supported for amp.

* Add testing of BF16 O1 and O2.

* support set master_grad

* move register_hook to auto_cast

* update unittest

* fix fp16 test

* update for review comments

* [AMP] Add python API for collecting operator stats.

* Fix import and polish codes.

* Add more unittest.

* Add doc for the new APIs.